From Abbot Nikon in Letters to Spiritual Children:
Who shall roll away the stone from the door of the sepulchre...for it (is) very great? (Mark 16:3). Who rolled it away? An angel, at God's command. He will likewise roll away the stone of insensibility from our hearts, when the time is right for this. We must show faithfulness to the Lord during times of callousness, faintheartedness, doubts, coldness, times of sorrow, illness and various misfortunes. We must exert our willpower to strengthen faith in ourselves when, by God's allowance, it seems to be all but extinguished. He permits this in order that we may show again and again what it is we are striving for, where our choice lies.
There is a saying among the elders: a good deed is either preceded or followed by a temptation. A good deed, such as heartfelt prayer, or especially Holy Communion, will not pass without the devil taking revenge. He uses all his might to prevent fruitful prayer and/or communion. If unable to achieve this, he then tries to spoil everything after the fact, so that not a trace of the benefit acquired remains. This is very familiar to all those who have some experience in spiritual endeavor. For this reason it is necessary to ask the Lord, with humility and contrition of heart, that He preserve us from the snares of the devil, who acts either directly upon the soul, or indirectly, through people subject to his power.
Do not be surprised at this. This warfare is fierce. Except the Lord build the house, in vain do they labour that build it. Except the Lord guard the city, in vain doth he watch that guardeth her, (Psalm 126:1-2). We must surrender ourselves into the compassionate hands of God, acknowledging before Him our weakness and inability to guard ourselves from visible and invisible foes. Do not be afraid. The devil does not do what he would like, but only that which God allows him to do. Take a look at the book of Job.
May God's blessing always be with you. Never despair. May Christ's Cross always serve to remind you of God's boundless love toward fallen man. Is this thought not enough to inspire one to wholly give oneself over into God's hands? One must make at least a small effort to seek the Kingdom of God, and then the Lord will not leave such a person without His help and comfort. The Lord loves you! Have patience with the Lord.
This beautiful meditation comes from the book Letters to Spiritual Children published by Nikodemos Orthodox Publication Society in New York in 1997.